Detective Inspector Dee Fielding, from Surrey Police, said: “He is incredibly confident, he’s incredibly violent and we believe he has specialist skills, which is not usual for the burglars we investigate.

“This individual does extensive research into the houses before he burgles them. We know he stakes them out.”

She said the man was likely to be ex-military and could wait for up to a couple of weeks in the garden or nearby, watching the routine of a home for when a back door would be unlocked.

Goodwood House

Victims reported the masked man appeared to know the house layout and about safes or valuables in the home, such as irreplaceable family heirlooms and engagement rings.

DI Fielding said the incidents had been traumatic for victims, who had been left in ‘absolute fear’ for their lives, and family members, including children, who were in the house at the time.

“There is senseless violence used against defenceless people in their own homes, the place where you think you should be safe,” she said. “This has been absolutely terrifying for victims.”

Police have linked thefts across Kent, Surrey, Thames Valley and Sussex at intervals of four to six months from 2014 to 2017, typically to large, secluded properties that left little opportunites for witnesses.

Unusual jewellery stolen in the seven aggravated burglaries, which are being linked. Photo from Surrey Police

Sussex Police detective inspector Till Sanderson said: “We carried out an extensive investigation into the robbery at Goodwood House and exhausted all lines of enquiry. Should any further information come to light we shall not hesitate to pursue new leads.

“We have worked with Surrey Police on their investigation and welcome this renewed appeal to bring this man to justice.”